import javax.crypto.Cipher;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Base64;

/**
 * 尝试不同的RSA padding模式解密ep
 */
public class TestRSAPaddingModes {
    
    private static final String EP_BASE64 = "qt0AJsNLEfayUx7S15jLfmQvMOpW6JJ+jCoxeXxn676R2OiN6xpLIQWSYe8ETFUF4+AaGrVY1wMCdyUPVaHM0J+8m+q/PUFgbiP3N8xSKQc4lIzzZuckbybYiFuLbEhcblmy162S5B70UJxzB6grhIVpsG/h0uw+JPaS2yTPpPVCiN/SImdOw2g12cun6niAwRZSQktZikzzbjwkRoiO8ehrwlAFJircnT1/1zba2oaGXLc/yU6cM2vWgJdyyoXJF4Mo/5XNBTDT+8yr1hPC5MKHWcTBB/isrRTD5CczInLgXHl48KKz18GkpPM7MML1GHb4pIjfTvu8hv/SLLW0sg==";
    
    private static final String PRIVATE_KEY_PEM = 
        "MIIEvAIBADANBgkqhkiG9w0BAQEFAASCBKYwggSiAgEAAoIBAQCz8JyumzBRR1nj" +
        "dxPzCFpqWXrAUBiC4ycTbTDdWdpZkciwiXU5s/OxF5i7l+Hvwc9Ggjph/PKo7PpW" +
        "hxZpzyEGpd6yVN9jAjJOt23o2TesgK8L/DAMhdJL8gNxKAQumbGF+ebMbcS8jWLx" +
        "vDAqpmnEW8VdCLEjF6uqOPtcDmIkBF83W6oaeu32DzTr/NS16sUGQKxlflo9qPOl" +
        "7VtcIsbR52klKK4uIyY23tWCouiyG84c/Uit+PleD5EYUGEu3p7IAAG5uJNzeUd0" +
        "UjZDhy6x7ue+kGgcCmCNQ4zSS/bQHMknalwqJUvUSxtIf8dq+/D78m7d4Zt9n9ZD" +
        "27t4Z2jHAgMBAAECggEAAr15RVdrpvE1NzeLADpyVghCzEbr+KJI6AzTn6tMneyQ" +
        "Z8/QDy7kWSAI3WJ0uFf1Nhepl/BoKZZiQYsRFk9nK1i/SWvtcu6HoZc9fzw/ksrq" +
        "333ZpXcsOqfW0ZRQa/0/LNEfaKGLS2vDw/afrSaXmbvkB4SoXeZwYMk5Wq+FYxL/" +
        "alrNpg/lzdvBlsCsTDA0G2RZrUVaO5yRTLRisBU+i8yORgnGkEwWvKpZYSFogCHS" +
        "iYHiNXFy//C+sYWlK7DjmG8/+krKhqBRRfdeg7LFThHQpbEGTtueD57jw0PCo2yr" +
        "6dqTvW9Qys+aWVNJk7RHNaI0yBFKWPadaHi3/olzkQKBgQDmz/FDpztS0fjKDIOj" +
        "gDyE76Z6dRFenmKJM1eOFt+MniY6/vi4ylU51/Etm4k6dNJ1MVBoFfyT9X0U/4k7" +
        "GNNUfIxMCJztUgY6EaCCt+09wk8pIvmOlRCmtxGwvmVC4nJVgUj3XJQ+wseblAkk" +
        "W0+IuT3GKX0CdKFMU4q9aucLYwKBgQDHk3rQ8Ae4ci4oj+MehRI29SNpcXG6OHbr" +
        "Z2EdsgqiFC1o/qv0269jtmCP7IqkGMdhTQrVetTHjZNZJH2bvUZ4o/0YT2+TTFPI" +
        "kTb2/a0txUTBTKrbnAdXh/iPFZAGvBROEDN0MNKo/vGAfi0K836DeTyBIaYongm6" +
        "6Rn6pwnUTQKBgBveVaougfoxAhIbSrWuISCH8xjsE6nSA+G/Aj5Uwq8u1TzgVlWx" +
        "kHLIgQVZt0sImfSufJ/kr7eJt42WgRJSoAmedC4mCBSbh8bxI+lEne+MC5TS9UDi" +
        "/Ly0c/1cL8vQna93ScEcO4YMbJ97U1NBdyvx+eR4U/C89lDJ8YGHa9gzAoGAQ6sY" +
        "sHFCXOKyDeTDoFyEUYgKqrzhT7/HaofR4Oy2OEBZKUl4anx2WnvC/+m3FG6mY7Jo" +
        "ovuT29mABXCe+khR9aO8tBpy/WGa4t2B4nse1e8WIehp4i5kOuSKfZFVFUN+Kv3J" +
        "RHMtakmO/v9JLHZlBhT8U9hh61GygOJ6gYdTiN0CgYAFz9iPy/xqLOUwiTNp3Imz" +
        "hdZo9ol3Qlr9CfMWMFHqRA5AyYvly9ZzxTpUCpSA+qz6OXqAjJ0bhGQxW2KHpmcT" +
        "yNGOPPca2vCaW8Mb1NTQueXpUBqX7alIkrRjUUyULteLb8FtyYl7mR3TVIu3FoO5" +
        "anNwDZ+2y7R9WUEiOzY3NA==";
    
    public static void main(String[] args) {
        try {
            System.out.println("=" + "=".repeat(99));
            System.out.println("测试不同的RSA Padding模式");
            System.out.println("=" + "=".repeat(99));
            
            byte[] epEncrypted = Base64.getDecoder().decode(EP_BASE64);
            byte[] privateKeyBytes = Base64.getDecoder().decode(PRIVATE_KEY_PEM);
            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
            
            String[] paddingModes = {
                "RSA/ECB/NoPadding",
                "RSA/ECB/PKCS1Padding",
                "RSA/ECB/OAEPPadding",
                "RSA/ECB/OAEPWithSHA-1AndMGF1Padding",
                "RSA/ECB/OAEPWithSHA-256AndMGF1Padding"
            };
            
            for (String mode : paddingModes) {
                System.out.println("\n" + "-".repeat(100));
                System.out.println("测试模式: " + mode);
                
                try {
                    Cipher cipher = Cipher.getInstance(mode);
                    cipher.init(Cipher.DECRYPT_MODE, privateKey);
                    byte[] decrypted = cipher.doFinal(epEncrypted);
                    
                    System.out.println("✅ 解密成功！长度: " + decrypted.length + " 字节");
                    System.out.println("\n前64字节:");
                    System.out.println(bytesToHex(decrypted, 0, Math.min(64, decrypted.length)));
                    
                    if (decrypted.length > 64) {
                        System.out.println("\n后64字节:");
                        System.out.println(bytesToHex(decrypted, Math.max(0, decrypted.length - 64), decrypted.length));
                    }
                    
                    // 检查是否有32字节的连续非零块
                    System.out.println("\n分析结构:");
                    analyzeStructure(decrypted);
                    
                } catch (Exception e) {
                    System.out.println("❌ 解密失败: " + e.getMessage());
                }
            }
            
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    private static void analyzeStructure(byte[] data) {
        // 统计零字节
        int zeroCount = 0;
        for (byte b : data) {
            if (b == 0) zeroCount++;
        }
        System.out.println("零字节数量: " + zeroCount + " / " + data.length);
        
        // 查找连续的32字节非零块
        for (int i = 0; i <= data.length - 32; i++) {
            boolean hasZero = false;
            for (int j = i; j < i + 32; j++) {
                if (data[j] == 0) {
                    hasZero = true;
                    break;
                }
            }
            if (!hasZero) {
                System.out.println("找到32字节非零块，位置: " + i + "-" + (i+32));
                System.out.println("  内容: " + bytesToHex(data, i, i + 32));
            }
        }
    }
    
    private static String bytesToHex(byte[] bytes, int start, int end) {
        StringBuilder sb = new StringBuilder();
        for (int i = start; i < end && i < bytes.length; i++) {
            sb.append(String.format("%02x", bytes[i]));
            if ((i - start + 1) % 16 == 0 && i < end - 1) {
                sb.append("\n");
            } else if ((i - start + 1) % 4 == 0) {
                sb.append(" ");
            }
        }
        return sb.toString();
    }
}


